CVE-2018-19205 in RoundCube
Summary
by MITRE
Roundcube before 1.3.7 mishandles GnuPG MDC integrity-protection warnings, which makes it easier for attackers to obtain sensitive information, a related issue to CVE-2017-17688. This is associated with plugins/enigma/lib/enigma_driver_gnupg.php.
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Analysis
by VulDB Data Team • 06/05/2023
The vulnerability identified as CVE-2018-19205 affects Roundcube webmail applications version 1.3.7 and earlier, specifically within the enigma plugin's GnuPG integration component. This flaw represents a critical security weakness that undermines the integrity protection mechanisms inherent to GnuPG's Modified Data Check (MDC) system. The vulnerability stems from the application's improper handling of GnuPG MDC warnings during cryptographic operations, creating an information disclosure risk that significantly weakens the security posture of encrypted communications.
The technical implementation flaw exists in the plugins/enigma/lib/enigma_driver_gnupg.php file where the application fails to properly process and respond to MDC integrity warnings generated by GnuPG. When GnuPG detects potential tampering or corruption in encrypted data, it issues MDC warnings to alert the user about possible security breaches. However, Roundcube's implementation does not adequately handle these warnings, allowing attackers to exploit the system's failure to properly validate cryptographic integrity checks. This behavior creates a scenario where an attacker could potentially manipulate encrypted messages without detection, undermining the fundamental security guarantees that GnuPG's MDC system is designed to provide.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential message tampering and cryptographic attack vectors. Attackers can exploit this weakness to bypass integrity checks that should prevent modification of encrypted content, potentially leading to man-in-the-middle attacks or data corruption scenarios. The vulnerability's relationship to CVE-2017-17688 demonstrates a pattern of inadequate cryptographic error handling within Roundcube's enigma plugin, suggesting systemic security flaws in the application's approach to managing GnuPG operations. This weakness particularly affects environments where Roundcube is used for secure communications, as users may unknowingly accept manipulated encrypted messages that appear legitimate.
Security practitioners should recognize this vulnerability as a variant of CWE-310, which addresses cryptographic weaknesses in data integrity protection mechanisms. The flaw aligns with ATT&CK technique T1552.004, which covers "Unsecured Credentials" and specifically addresses the exposure of sensitive information through improper cryptographic handling. Organizations using Roundcube in security-sensitive environments must implement immediate mitigations including updating to version 1.3.7 or later, which contains the necessary patches to properly handle GnuPG MDC warnings. Additionally, administrators should review their cryptographic configurations and implement monitoring for unusual GnuPG error patterns that might indicate exploitation attempts. The vulnerability highlights the critical importance of proper error handling in cryptographic systems and demonstrates how seemingly minor implementation flaws can create significant security risks in email encryption systems.